### Earth Layers --- #### Review: How is a magnetic field created? Electromagnetic Force <img src="/assets/slides/earth_magnetic_field.jpg" style="margin: 0 auto; display: block;"> --- #### What's in the earth's core? <iframe style="margin: 0 auto; display: block;" width="560" height="315" src="https://www.youtube.com/embed/XXTEWQdu3aE?si=dO2A7zruCtHHOSeo" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe> --- #### The magnetic field comes from Earth's spinning inner and outer cores <img src="/assets/slides/innercore.jpg" style="margin: 0 auto; display: block;"> --- - The inner core is primarily composed of an iron-nickel alloy with some other elements. It is believed to be a solid ball made mostly of iron, with temperatures estimated to be around 5700 K, similar to the surface of the Sun. - The outer core is primarily composed of liquid iron and nickel. It also contains light elements such as sulfur, oxygen, and small amounts of hydrogen and carbon, which help lower its density compared to pure iron. <!-- .element: class="fragment" data-fragment-index="1" --> --- #### Earthquakes and Seismology in Earth's Interior <iframe style="margin: 0 auto; display: block;" width="560" height="315" src="https://www.youtube.com/embed/Prey5z8WQiU?si=gChY2Kj5y3azKS1a" title="YouTube video player" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share" referrerpolicy="strict-origin-when-cross-origin" allowfullscreen></iframe> --- #### What are seismic waves? - Vibrations that rumble through the Earth. <!-- .element: class="fragment" data-fragment-index="1" --> - Surface waves are the seismic waves that travel along the Earth's crust. They destroy things. <!-- .element: class="fragment" data-fragment-index="2" --> - Body waves are the seismic waves that travel through the Earth's interior. <!-- .element: class="fragment" data-fragment-index="3" --> --- <img src="/assets/slides/pswaves.png" style="margin: 0 auto; display: block;"> --- #### Wave interaction depends on 1. Density 2. Temperature 3. State of rock --- #### How do P and S Waves tell us about the interior of the Earth? <img src="/assets/slides/pswaves2.jpg" style="margin: 0 auto; display: block;">